The present invention relates to closure arrangements designed for use with tubes or other containers where the closure body is used to define the neck of the container. Such closure arrangements usually comprise a shoulder portion, which is fixed to one end of the container and defines a dispensing passageway, and a cover portion adapted to seal the dispensing passageway when the container is not in use.
In particular, the invention relates to a closure arrangement where the shoulder portion is made from a material which cannot be directly bonded to the container, such as a barrier material for example. Traditionally, tube closure arrangements of this type are manufactured from HDPE. Tube shoulders made from HDPE can be directly bonded to the laminate ABL or PBL tubes. However, modern preparations, such as toothpaste for example, require the tube shoulder to be manufactured from a barrier material. Unfortunately such barrier materials will not bond with the laminate tube material. Therefore, in such cases, the closure arrangement further comprises a fixing ring, made from a material which is compatible with the tube laminate material and will bond thereto. The fixing ring is adapted to fit around the periphery of the tube shoulder. Usually, the fixing ring is assembled on the tube shoulder prior to the assembly being sealed into the tube. Because the tube shoulder and fixing ring are made of different materials, which will not bond with each other, it is necessary to provide a mechanical lock between the two components to prevent them from becoming separated.
The material used for the tube shoulder is often not suitable for forming an integral hinge between it and the cover portion. Therefore, if a hinged cover is desired, a separate closure comprising a body and a lid has to be provided, made from a material which is suitable for forming an integral hinge. The closure body is provided with mechanical engagement means, such as screw threads or snap beads, to hold it in place on the tube shoulder, which has cooperating threads or snap engagement means. Thus, a typical hinged tube closure arrangement comprises 3 parts; a tube shoulder, a fixing ring to bond the tube shoulder onto the tube, and a separate hinged closure. The tube shoulder and fixing ring have to be assembled prior to fixing the assembly onto the tube. The separate closure also has to be applied to the neck portion of the tube shoulder.
One aim of the present invention is to remove the requirement for assembly of the closure arrangement by using sequential moulding techniques to mould the shoulder, fixing ring and cover as a single component. Another aim of the invention is to provide a hinged closure arrangement, in which the cover portion is hinged directly to the shoulder or the fixing ring. Yet another aim of the invention is to use this technique to provide tamper-evidence to indicate if the cover has been opened.
Accordingly, the present invention provides a closure assembly comprising a body adapted to form the neck of a container, having a depending skirt and defining a dispensing passageway, a cover arranged to cooperate with the body to seal the dispensing passageway, and a fixing ring arranged around the periphery of the depending skirt for connecting the body to the container, the cover and fixing ring are sequentially moulded over the body, and the cover and fixing ring being moulded integrally with one another, characterised in that the cover is connected to the body or the fixing ring by a sequentially moulded hinge.
The connection of the cover and fixing ring together as a unitary component, which is sequentially moulded around the shoulder, has several advantages. First, there is no need to assemble the various components of the closure arrangement prior to affixing it to the container. Also the connection between the cover and the fixing ring may be-adapted to provide a mechanical key between the fixing ring and the shoulder to prevent them becoming disassociated either prior to or during use.
Advantages of providing a hinge between the cover and the shoulder or the fixing ring include, for example, that the cover is retained on the container and the cover can be pivoted through a large angle and therefore held clear of the dispensing passageway.
A mechanical hinge may be sequentially moulded between the cover and the shoulder to provide a simple, inexpensive hinged closure. The dissimilar materials of the cover and the shoulder means that these components will not bond to one another and the two hinge parts will be able to move relative to one another, thereby allowing the mechanical hinge to operate.
Alternatively, a hinge section may be moulded between the cover and the fixing ring. The advantage of the arrangement according to the invention is that conventional materials may be used for the cover and the fixing ring and hence conventional hinge configurations can be moulded between these components, such as a simple film hinge or snap hinge.
The arrangement of the hinge and the fixing ring has implications for heat sealing the fixing ring to the container. If the hinge is radially inwardly displaced of the fixing ring this allows the use of axial heat sealing equipment. If the hinge is radially outwardly displaced, axial heat sealing is not possible and radial heat sealing must be used. Axial heat sealing is simpler and is generally preferred for such applications.
Advantageously, the cover and the fixing ring are connected by thin sections, which are broken on first opening of the closure to provide visible tamper-evidence. The connection between the cover and the fixing ring may be adapted to provide a mechanical key between the fixing ring and the shoulder. Preferably, the connection between the fixing ring and the cover defines a strap or straps to key the fixing ring and shoulder together to prevent relative movement between the two. The mould cavity for the straps provides a flow path between the cover and the fixing ring to allow the molten plastics material to pass from the cover mould cavity into the fixing ring mould cavity. Preferably the strap or straps are connected to the cover by the thin sections previously described.
As described above, the cover and fixing ring may be connected by thin sections which can easily be broken by a user to allow the cover to be opened. Alternatively, the two components may be connected by thicker portions which have to be cut prior to first opening. Thin sections may be left after the cutting procedure to provide frangible bridges which are broken by the user when the cover is opened for the first time. The latter has the advantage that it is easier to manufacture because the mould will have larger cavities, providing a larger flow path for the molten plastic. However, the former has the advantage that a separate cutting operation is not required.
Many applications require the use of barrier materials to form the shoulder because this part of the closure arrangement is in contact with the product. Hence, the shoulder is preferably produced from a suitable barrier material such as PET or PBT to protect the product, reducing flavour loss and scalping for example. The material used for the fixing ring must be compatible with the material used for container, such as the laminate material used for tubes for example, so that the fixing ring can bond the shoulder onto the container. HDPE is a suitable material for the fixing ring and also has good properties for the cover. For example, it can be used to form conventional hinges and provides a good seal against the dispensing aperture formed in the PET/PBT shoulder, to prevent product leakage.